A kind of silicon@carbon/mxene ternary composite material for lithium ion battery and its preparation method

A technology for lithium-ion batteries and composite materials, applied in the field of silicon@carbon/MXene ternary composite materials for lithium-ion batteries and its preparation, can solve problems such as poor preparation effect, difficulty in forming a uniformly dispersed composite structure, and severe MXene agglomeration , to achieve the effect of increasing the contact reaction area, improving the high current rate performance, and stabilizing the cycle performance

Active Publication Date: 2021-06-15
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the currently reported methods for preparing Si / MXene composites are usually simple ultrasonic mixing or vacuum filtration, etc., the MXene agglomeration is serious, it is difficult to form a uniformly dispersed composite structure, and the preparation effect is poor.

Method used

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  • A kind of silicon@carbon/mxene ternary composite material for lithium ion battery and its preparation method
  • A kind of silicon@carbon/mxene ternary composite material for lithium ion battery and its preparation method
  • A kind of silicon@carbon/mxene ternary composite material for lithium ion battery and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] (1) Weigh 0.2423g C 4 h 11 NO 3 Dissolve in 200ml deionized water to make 0.01mol / L Tris buffer. Weigh 100 mg of nano-silicon material with a size of about 90 nm and ultrasonically disperse it in Tris buffer, add 100 mg of dopamine hydrochloride, stir for 24 hours, and collect it by centrifugation to obtain Si@polydopamine material, that is, polydopamine-coated silicon material, such as figure 1 shown;

[0032] (2) Re-disperse the Si@polydopamine material in 100ml deionized water, add 25ml MXene dispersion (2mg / ml), stir for 1h and then vacuum filter to obtain the Si@polydopamine / MXene material (mass ratio, Si:MXene =2:1);

[0033] (3) Transfer Si@polydopamine / MXene to a vacuum oven, and vacuum treatment at 60°C for 6 hours, so that the secondary amine groups of polydopamine and the hydroxyl groups on the surface of MXene undergo a crosslinking reaction to form covalent bonds or hydrogen bonds;

[0034] (4) The cross-linked Si@polydopamine / MXene was placed in a tub...

Embodiment 2

[0041] (1) Weigh 0.2423g C 4 h 11 NO 3 Dissolve in 200ml deionized water to make 0.01mol / L Tris buffer. Weigh 100 mg of nano-silicon material with a size of about 90 nm and ultrasonically disperse it in Tris buffer, add 100 mg of dopamine hydrochloride, stir for 24 hours, and collect by centrifugation to obtain Si@polydopamine material;

[0042] (2) Redisperse the Si@polydopamine material in 100ml deionized water, add 100ml MXene dispersion (2mg / ml), stir for 1h and then vacuum filter to obtain the Si@polydopamine / MXene material (mass ratio, Si:MXene =0.5:1);

[0043] (3) Transfer Si@polydopamine / MXene to a vacuum oven, and vacuum treatment at 60°C for 6 hours, so that the secondary amine groups of polydopamine and the hydroxyl groups on the surface of MXene undergo a crosslinking reaction to form covalent bonds or hydrogen bonds;

[0044] (4) The cross-linked Si@polydopamine / MXene was placed in a tube furnace and treated at 600 °C for 2 h under an argon atmosphere to obta...

Embodiment 3

[0048] (1) Weigh 0.2423g C 4 h 11 NO 3 Dissolve in 200ml deionized water to make 0.01mol / L Tris buffer. Weigh 100 mg of nano-silicon material with a size of about 90 nm and ultrasonically disperse it in Tris buffer, add 100 mg of dopamine hydrochloride, stir for 24 hours, and collect by centrifugation to obtain Si@polydopamine material;

[0049] (2) Redisperse the Si@polydopamine material in 100ml of deionized water, add 12.5ml of MXene dispersion (2mg / ml), stir for 1h and then vacuum filter to obtain the Si@polydopamine / MXene material (mass ratio, Si: MXene=4:1);

[0050] (3) Transfer Si@polydopamine / MXene to a vacuum oven, and vacuum treatment at 60°C for 6 hours, so that the secondary amine groups of polydopamine and the hydroxyl groups on the surface of MXene undergo a crosslinking reaction to form covalent bonds or hydrogen bonds;

[0051] (4) The cross-linked Si@polydopamine / MXene was placed in a tube furnace and treated at 600 °C for 2 h under an argon atmosphere to...

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Abstract

The invention relates to the field of negative electrode materials for lithium-ion batteries, and discloses a silicon@carbon / MXene ternary composite material for lithium-ion batteries and a preparation method thereof. The silicon@carbon / MXene ternary composite material is a ternary composite material obtained by performing a self-polymerization reaction of dopamine hydrochloride on the surface of a silicon material to form a polydopamine layer, and then mixing and cross-linking with MXene in a liquid phase, followed by high-temperature treatment. In this method, the secondary amine group of polydopamine on the surface of the silicon material can undergo a crosslinking reaction with the hydroxyl group on the surface of the MXene to form a covalent bond or a hydrogen bond, thereby inhibiting the agglomeration of the silicon material and MXene and improving the electrochemical performance of the silicon material. Among them, the size of the silicon material is 20-500nm, the thickness of the carbon coating layer is 3-10nm, and the mass ratio of silicon to MXene is (0.5-4):1. The resulting silicon@carbon / MXene ternary composite has a pore volume of 0.05‑0.3 cm 3 / g, the specific surface area is 60‑120m 2 / g. The silicon@carbon / MXene ternary composite material is used as the anode material of lithium-ion batteries, showing excellent cycle performance and rate performance.

Description

technical field [0001] The invention belongs to the field of negative electrode materials for lithium ion batteries, in particular to a silicon@carbon / MXene ternary composite material for lithium ion batteries and a preparation method thereof Background technique [0002] Lithium-ion battery is a new type of high-energy battery successfully developed in the 20th century. Due to its charging and discharging process, Li + It is embedded or extracted back and forth between the two electrodes, so it is aptly called a "rocking chair battery". Lithium-ion batteries have the advantages of high storage energy density, long service life, no memory effect, and environmental protection. They have received more and more attention and have been widely used in portable electronic devices, electric vehicles, and aerospace. However, the performance of current commercial lithium-ion batteries cannot meet people's demand for high energy and high power density, so electrode materials with hig...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525
CPCH01M4/364H01M4/386H01M4/587H01M4/625H01M10/0525H01M2004/027Y02E60/10
Inventor 徐斌张鹏朱奇珍
Owner BEIJING UNIV OF CHEM TECH
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